AUGERED PILE CLASSIFICATIONS

Transcription

1 AUGERED PILE CLASSIFICATIONS Figure 1. Nomenclature used for Auger Piles in Europe and the USA (Prezzi and Basu 2005).

2 DEEP FOUNDATIONS: CAST-IN-PLACE (CIP) PILES Table 8-1. FHWA NHI (from NAVFAC DM7.02). ACIP Auger Cast In Place DD Drilled Displacement CFA Continuous Flight Auger APG - Auger Pressure Grouted APGD - Auger Pressure Grouted Displacement

3 CFA PILES: CONSTRUCTION PROCESS Figure courtesy of Trevispa.eu Figure 2.2. Schematic of CFA Pile Construction (FHWA GEC-8 from Bauer).

4 CFA PILES: CONSTRUCTION PROCESS Balanced auger rotation and penetration rates (No Lateral Feed ). Excessively slow penetration rate and an insufficient base feed to keep the auger flights full (Lateral Feed ). Figure 2.5. Effect of Over- Excavation using CFA Piles (FHWA GEC-8 after Fleming 1995).

5 DRILLED DISPLACEMENT* PILES: DRILLING TOOLS * SCREW PILES Figure 2.1. Drilling tools for installation of different drilled displacement piles (Basu and Prezzi 2009).

6 DRILLED DISPLACEMENT PILES: AUGER PRESSURE GROUTED DISPLACEMENT (APGD) Patented by Berkel & Company Contractors. Loose to Med. Dense Sands (N<25) m OD Up to 24m Long Figure 2.1. Installation stages for APGD piles (Basu and Prezzi 2009).

7 DRILLED DISPLACEMENT PILES: DUAL-DISPLACEMENT, CIP CONCRETE PILE (ATLAS) See De Cock and Imbo (1994) m OD m (Enlarged Flange) Up to 25m Long Figure 2.3. Installation stages for Atlas piles (Basu and Prezzi 2009).

8 DRILLED DISPLACEMENT PILES: DEWAAL PILES Morris-Shea has exclusive US rights. Consists of a sacrificial tip, a partial-flight auger and a displacement body. 1-2ft OD Up to 120ft Long Figure 2.4. Installation stages for DeWaal Piles (Basu and Prezzi 2009).

9 DRILLED DISPLACEMENT PILES: American Pile Driving Inc. in US. A casing/tube with a conical auger tip attached to its end is rotated clockwise and pushed down into the soil m OD Up to 25m Long FUNDEX PILES Figure 2.5. Installation stages for Fundex Piles (Basu and Prezzi 2009).

10 DRILLED DISPLACEMENT PILES: OMEGA PILES Malcom Drilling & L.G. Barcus & Sons. Grout is injected under pressure into the casing even before the desired depth is reached. Figure 2.7. Installation stages for Omega Piles (Basu and Prezzi 2009).

11 CFA PILES: GEOTECHNICAL CONDITIONS FAVORABLE Medium to Stiff Clay Soils. Cemented Sands or Weak Limestone. Residual Soils. Medium dense to dense silty sands and well-graded sands. Rock overlain by stiff or cemented deposits. Figure courtesy of DFI After FHWA GEC-8

12 CFA PILES: GEOTECHNICAL CONDITIONS UNFAVORABLE Very soft soils. Loose sands or very clean uniformly graded sands under groundwater. Residual Soils. Geologic formations containing voids, pockets of water, lenses of very soft soils, and/or flowing water. Hard soil or rock overlain by soft soil or loose, granular soil. Sand-bearing stratum underlying stiff clay. After FHWA GEC-8

13 CFA PILES: GEOTECHNICAL CONDITIONS Figure courtesy of Rockal.com UNFAVORABLE Highly variable ground conditions. Conditions requiring penetration of very hard strata. Ground conditions requiring uncommonly long piles (>100ft). Ground conditions with deep scour or liquefiable sand layers. After FHWA GEC-8

14 CFA PILES: PROJECT CONDITIONS CFA VIABLE WHEN: Projects where speed of installation is important. Batter Piles Required. Projects where large numbers of piles are required. Low headroom conditions. Rock overlain by stiff or cemented deposits. After FHWA GEC-8 Figure courtesy of SoilMec

15 DRILLED DISPLACEMENT PILES ADVANTAGES Better performance in loose sandy soils. Little or no spoil removed from site. DISADVANTAGES Difficult to penetrate dense or hard soils and more limited depth range. Effect of displacement. After FHWA GEC-8 Figure courtesy of Morris Shea Bridge Co. Inc.

16 DRILLED DEEP FOUNDATIONS PILE CAPACITY PREDICTION METHODS: CPT BASED (PARTIAL LIST) Schmertmann Method (1978) De Ruiter and Beringen Method (1979 Penpile Method (1980) Prince and Wardle Method (1982) Tumay and Fakhroo Method (1982) Aoki and De Alencar Method (1975) Philipponnat Method (1980) LCPC (Bustamante and Gianeselli) Method (1982) Almeida et al. Method (1996) MTD (Jardine and Chow) Method (1996) Eslami and Fellenius Method (1997) Powell et al. Method (2001) UWA-05 Method (2005) Zhou et al. Method (1982)